Light-element nucleosynthesis from jet-cloud interactions in active galactic nuclei

The production of light nuclei via the interactions of jets from the central engines of active galactic nuclei and the surrounding medium is studied. Several environments ranging from hot, dense knots of gas near the central engine to the cold broad-line region clouds are simulated by a nuclear reaction network that couples the thermonuclear processes in the cloud to the reactions between the jet particles and the cloud. Reaction products from the jet-cloud interactions are followed until they react or are thermalized, which may involve several subsequent reactions. The effects of nucleosynthesis from the introduction of a jet into the cloud can result in enhanced production of light nuclei well above their primordial abundances, and enhancement of CNO nuclei is also predicted above thermally produced abundances. In these scenarios, the jets can enhance abundances of CNO nuclei by first producing excess amounts of nuclei with A < 8, then by increasing the cloud density to the point at which the thermonuclear reaction rates become important. The comparison to observed abundances in quasars leads to the conclusion that the interactions of ejected matter from AGNs may be responsible for large observed abundances of light nuclei in addition to significant abundances of nuclei in the CNO region.